Disclaimer



y 2 w. H. BASSETT Re. 17,296

HOLLOW CNDUCTOR Original Filed Oct. 3, 1924 nontoz %MLM/Mafi 5633572:2331 & c temet; I,

eissued May 21; 1929.

UNITED STATES PATENT OFFICE.

WILLIAM E. ,BASSET'L OF CHESHIRE, CONNECTICUT, ASSIGNOR TO THE AMERICANBRASS COMPAN Y, OF WATERBURY, CONNECTICUT, .A. COBPORATION OF CONNECTI-GUT.

' EOLLOW CONDUCTOB.

Original Re. 1,597,422, dated August 24 1926, Serial Ne. 741543, filedOctober 3, 1924. Reissue No. 17,156, dated December 11, 1928, Serial Ho.19%,124 :lied May 17, 1927. This application !or reissuc filed February14, 1929. Serial No. astma.

My invention relates to hollow conductors which are of relatively largediameter for a given cross-sectional area of the conduetng material soas to permit them to be used for high voltage transmission withoutsubstantial corona loss or for other purposes requiring maximum diameterand surface with reduced cross-section of conducting material, and hasfor its object to produce a new and improved hollow conductor of therequired flexibility; high resistance to mechancal n- 'ury liable toresult from crushing stresses, high tensile strength, maximum conduetingefliciency and relatively low weight. My

improved conductor may be used bare or insulated as occasion requires.

Conductors heretofore made have been open to 'various objections. Thus,solid conductors of economic cross section when used for high voltagetransinssion are of such small diameter that the corona losses are sogreat as to rendor the transmission relatively inefiicient, adisadvantage which numerous inventors have attempted to overcome bymaking the conductors hollow and thus in- *creasing the diameter of theconductors relatively to the cross-sectional area of the conductingmaterial.

It has been proposed to make such hollow conductors in various ways, allwhich, however, have been found subject to certain disadvantages, whichit is the present invention to obviate.

A cable embodying my invention is shown in the accompanying drawing-s,in which F ig. 1 shows a portion of the cable partly in side elevationand partly broken away;

Fig. 2 shows a transverse section of the same on the line 2-2 of Fig. 1;

Fig. 3 shows a portion of the strip on an enlarged scale; and

Fi 4: shows, on an enlarged scale, a modified orn of strip. 4

Referring more particularly to the drawings, 2 represents a twistedstrip having at its edges lat'erally 'projecting portions or fiangesforming thickened edges or head 4-4 so as to make it substantiallyI-shaped in cross-section. The outer surfaces G-6. of these heads arecurved so as to substantially conform to the inner surfaces of wires orstrands cabled thereon. The central part 8 purpose of my of the bodyportion of the strip nay be thickened so as to give the strip g'eatertensile strength as 'shown in Fig.'4. The twisted strip is twisted aboutits longitudinal axis, the preferable pitch being about one completetwist to four inc'hes for a strip five-eighths of an inch in width. Astrip of such width whose body portion is .040 of an inch thick ao andwhose edges are .090 of an inch thck gives satisfactor results.

About the' twisted strip, wires or strands 10 are cabled and if desiredanother layer of wires or strands 12, thus makin up the com- 35 pletedcable as shown. As s own in the drawings the wires or strands are roundbut obviously that form of wire or strand is not necessary to theembodiment of the invention. In forming the cable the strip in untwistedform with its p'rojecting fianges' is first produced. It is then twistedas shown and then 'ed to a cabling machine where it is surroundedwithone or more layers of conducting wires or strands thus producing thecomplote cable.

The thickened edges of the core are of especial importance in connectionwith the manufacture of the cable. Where a fiat strip w is used, thestrip being twisted often suddenly changes from a spiral twist to ahelical twist or curl which would continue for a foot or more before itcould be stopped. In some cases in working with the fiat strip this hashappened so often as to spoil the entire lot even for experimentalpurposes. A single spot where the twist has changed ffbm a. spiral formto a helical form runs the core for commerical purposes. When the stripoo has the fianges described heroin this difliculty is eliminated,andcores many miles in length can be made without dfects in the twist.

The use of two and maybe more layers of conducting wires or strands, andof different sizes, as in Fig. 2, has a special value in the productionand use of the hollow style of cable. The metallic cross section isfixed by the requisite current carrying Capacity and the outsidediameter is fixed by the required 0 voltage and the altitude of theline. By making the conductor in two layers, the flexibility of thecable is improved and by using wires of different sizes in two layers,the combination of the determined current carrying capacity or metalliccross section and required outside diameter can be more closelyapproximated under the conditions of operation.

It is aisoinportantto have a comparatively wide hearing of the innerconducting wires on the core. A better cable to meet all these requiredconditions can be designed by using a pluralty of layers, each layermade oi strauds which in turn consist ot several wires and the wires orstrands in the cable being spiralled ,in the same direction or indifferent directions.

The flanges on the twisted strip constitute in effect a hollow spiralwith e comparatively wide hearing face for the strands, the body portionconstituting a comparatively narrow support extending hollow spiral; andthe invention includes various other constructions than thatspecifically illustrated embdying the combination of hollow core andinternal support.

Various other means than the flanges describedmay be 'used forstifl'cning the strip against longitudinel bendin and for thus opposingits changing from the desired spiral twist o a helical twist.

?he thickened edges of the core and the wires surrounding it, beinglocated remote from the center of the cable, are thercfore located wherethey act most effectively for conducting current, as it is well known thut 'alternating currenttends to be more desc es the distance froni thecenter of a eonductor is increased. T hus the metal in the core is sodistributed that it acts efliciently as a conducting path as well as asupporting mem-ber.

The same type of hollow conductor is ad- Vantageous for other purposesrequiring large diameter and surface with relativel small cross-sectionof conducting materia The major part of the conducting material,including the cabled wires and the flanges on the strip is distributedat the outer portions of the cable so that, when aiternating currentsare used at frequencies which tend to concentrate the current toward theoutside surface, the conducting material' is used efficiently. Moreoverthe amount of heat dissipated froni the hollow oonductor 'described isgrcater than from a conductor of equal cross section of conductingmaterial and smaller diameter. These considerations make the presentconductor Very useful not only for high Voltages but also for carryingextra heavy currents which would be usually at comparatively lowVoltages.

Vhile the core may be of the same material as the eonducting wires orstrands cabled about it, it may be made of other suitable metal eiloy. Ipreferabiy in :ike the conducting strands br wires of copper alloy andmake the twstml strip ot Copper or similar alloy. Such Copper or Copperalloys (which I refer to generically as cuprous metal) can beeffecacross the interier of the tively worked and provide the necessaryserength and Stress resisting eharacteristics. lVhere more th an onelayer of wires or strands are used they may be spiralled in either`direction but 1 'prefer to (table the inner iayer around in e directionopposite to the twist of the strip and the succeeding layer in the samedirection us the twist of the strip.

Various other nodifications may be made by those skilled in the artWithout departing from the invention as defined in the following claims.

What I claim is: i

1. In a condueting cable comprising a series of strands cabled so as toform a tube, a core formed by a twisted strip having thickenedconducting portions formin spiral surfaces engaged by said strands ansupporting the same. u

2. In a conducting cable comprising a series of strands cabled coreformed by a twisted strip having a body portion and projecting flangesforming thickened edges thereon, said fianges providing thickenedconducting portions and` spital surfaces engaged by said strends and supporting the same.

3.' 111 a conducting cable comprising a series of strands cabled so asto form a tube, a core formed of a twisted strip having a thin bodyportion and projecting flanges upon its edges so as to have an I-shapedcross-section, said flenges providing thickened conductin portions andspiral surfaces supporting sai strands.

4. In a conducting cable comprising a Series of strands cabld so as toform a tube, a core formed by a twisted stri having a body portion andprojectng anges forming thickened edges thereon, said fianges providingthickened conducti ng portions and spiral sur-faces engaged by saidstrands and sup porting the same, said spiral surfaces being curvedtransversely so as to substantialiy conform to the inner surface of thetube.

5, In a conducting cable comprising a series of strands cabled so as toform a tube, a core formed by &twisted strip having a body portion andprojecting flanges forning thickened edges thereon, said fiangesproviding thickened conducting portions and spirat surfaces engaged bysaid strands and supporting the same, said thickened conducting portionsbeing about twice as thick as the adjacent body portion. u

6. A conducting cablc comprsing a series of strands cabled so as to forma tube and a core including a twisted strip and means for stiffeningsaid strip against longitudinal bending.

7. In a eonducting Cable comprising a se ries of strands cabled so as toform a tube, a core tormed by a twisted strip having a body portion andprojecting fianges, said fianges forning a comparatively wide-facedspiral so as to form a tube, a'

beiring for the cabled strands and said body portion forming acomparatively nar-ow transverse support.

8. A flexible conductor which is hollow so as to have a comparatvelylarge external surface withreduced metallic cross-section, saidconductor comprising sti-amis cabled so as to form a tube, comparativelywide-faced spital hearing means for the internal surface of said tube ofcabled strands and comparetively narrow supporting means extendingdiametricellyacross the space between opposite portions of said beat-mgmeans.

9. A flexible conductor which is hollow so as to have a comparativelylarge external surface with reduced metallic cross-section, saidconductor comprising strands cabled so as to form a tube and artan ed inin a plurality of layers, the strands o the respective layers being ofdifferent sizes and bein of cup-ous v metale, comparatively wide-facespiralbearing means for the internal surface of said tube of cabledstrnds'and comparatively narrow supporting means extendng diametrically'across the space between opposite portions of said hearing means.

In witness whereof, I have hereunto signed my name.

DISCLAIMER Reissuu No. 17,296.-W21Z7'(m [1. Bassett, Cheshire, Umm.HULLOW (JoNnUc'ruk. atent dutecl May 21, 1929. Disclaimer filed March13, 1931, by the assignoe, The American. Bmss C'mpany.

Ilcreby enters this disclaimer to claim 6 of said spocfication which isin the following words, to Wit:

A conducting cahlc comprising a series of strands cabled so as to form atube and core including u twisted strip and means for stitl'cning saidstrip against longitudinal bendng.

[Ofiic'al Gazctte April 14, 1931.]

